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ndverdo writes "Cree just announced production power LEDs reaching 200 lumen/watt. Approximately doubling the previous peak LED light efficiency, the new LEDs will require less cooling. This should enable the MK-R series to finally provide direct no-hassle replacements to popular form-factors such as MR-16 spots and incandescent lighting in general. The LEDs are sampling and it is stated that 'production quantities are available with standard lead times.'"

The reduced cooling should help in lowering the costs of the LED versus the CFL and the reduced energy consumption will be a help as well.

Yesterday I went to Walmart to get new light bulbs, old CFLs I had burned out. There Walmart had LED bulbs in stock, at around $20 a bulb. I ended up going to Sam's to get CFLs, an 8 pack cost less than $6.

I don't know how it helps or interest someone else but I paid the equivalent of less than $10 for my 650 lumen ones but that was only because they was half price and when I bought it the half price was already in the register but the person selling them also pushed in 50% off so hence I only paid 25% of the original price. And I had actually looked at them at full price earlier because CFLs die so quickly at the toilet and bathroom.

I also bought 12v spotlights with LED. I wonder if I got the same price ther

And I had actually looked at them at full price earlier because CFLs die so quickly at the toilet and bathroom.

I have had 4 CFL globes in my bathroom for nearly 4 years, and have replaced only one bulb so far. In general, CFLs seem to have a worst case of about 5-6 times the life of an incandescent in the same fixture. I also like the fact that I can get more light when the fixture is wattage/heat limited.

Other than not being able to use dimmers, the biggest complaint I have with CFLs is that now it's tough to buy just one or two without paying a huge premium. The multi-bulb packs are sometimes so much cheaper pe

Sure it will cost more than the very cheapest CFLs but it's 5 or so times more, not 50 times more. And that's more than my LED lights are rated at (the ones I bought it's even highly rated.)

Regarding the rating and heat I think it make total sense to at least be able to put a similar power rated light-bulb in the same fixture considering the higher efficiency. I'm not 100% sure it work like that but I can't understand why it shouldn't. Using LEDs those cooling fins get hot but then again a regular lightbulb get very hot to.

You can get CFLs usable with dimmers to. I think what people should take home with them is that you should buy the CFL which fit your needs, not just any CFL. If it's going to be on for long sure buying any may be ok. If it's going to go on and off often buy one for that, if it need to be dimmable buy one for that and if it will be sitting outside like here and may have a -20 degree C around it buy one designed for that.

please post the model number of the dimmer, because my 5 Philips LED bulbs in my family room on a Lutron dimmer don't go below about 20% before flicking out, and worse yet, if you have them right at 20% or so and the freezer kicks in, they turn off and don't come back on until you adjust the dimmer again.

These things come with warranties? @ $20+ dollars per bulb, I'd be pretty pissed if the thing burned out after several months.

As I said in my original post, I bought an 8 pack of CFLs for less than $6. The first CFL I bought cost $20, but that was more than 25 years ago and it lasted about 15 years before burning out. Between the cost of the bulb, how much energy it saved, and how long it lasted I believe I saved money paying more to buy it than the total cost of buying incandescent bulbs instead.

I think that's enough examples to show there are inexpensive dimmable CFL bulbs. However Walmart has more.

CFL sucks. We're better off with incandescent in the meantime.

I've used CFLs for more than 20 years and have not had a problem with them. That's not entirely true, I have had problems with them. In photography, photos on film show color casting with florescent bulbs, and with incandescent bulbs as well. The first CFL I bought I paid $20 for, and over the next 15 years it paid it's cost back in avoided cost. That is in energy not used and in not having to replace incandescent bulbs. I wonder if you enjoy wasting money.

CFLs are most often killed by high temperatures, not poor power. Many older light fixtures (possibly even most) are fully enclosed because they were designed for incandescent bulbs. The fixtures got very hot but not so hot as to cause a fire. The problem with CFLs is that even though they use less power and result in less heat, the ambient temperature inside a fully enclosed fixture will result in premature failure. Very few new fixtures on the market are fully enclosed for this reason.

The next most common cause of CFL failure that I've seen is CFLs being placed on dimmer switches. People don't read the warning label on the package and try to use regular CFLs with dimmer switches all the time. Don't expect those bulbs to last long.

And finally, with regards to poor power... Just as dimmer switches will cause a CFL to eventually fail, power spikes and sudden drops will have the same impact. If you wiring is bad or you have a noisy device attached to power, the cheap CFLs can die early. Had a MacPro with a bad power supply cause a hum in the lines that could be heard the next house over if you listened to the CFLs. It would only happen with drawing a significant amount of power - in my case, rendering video. Serves as a good example of how if you have premature failure then there's something that needs to be fixed - or else you are asking for other, more expensive problems.

CFLs are most often killed by high temperatures, not poor power. Many older light fixtures (possibly even most) are fully enclosed because they were designed for incandescent bulbs. The fixtures got very hot but not so hot as to cause a fire. The problem with CFLs is that even though they use less power and result in less heat, the ambient temperature inside a fully enclosed fixture will result in premature failure. Very few new fixtures on the market are fully enclosed for this reason.

You must be living in bizzaro world where everything is opposite. Many homes and shops used to have those recessed spots and the filament bulbs would fail every few months due to heat, but as soon as they were replaced with CCFLs they could last for years. Aside from anything else the shape of the CCFLs was narrower and thus allowed airflow, where the filament spots filled up the hole almost perfectly.

Similarly those almost enclosed wall lights and desk lamps kill incandescent and halogen bulbs much faster

Tungsten bulbs reached the point of being a commodity item years ago - there really is very little to choose between one 60W tungsten bulb and another.

Problem is, this means people expect the same thing from CFLs. Why not? They're sold in the same part of the store with similar packaging to do a similar job, many stores only carry one brand and they're outwardly all very similar, it's hard not to make that assumption.

But the actual products vary hugely in terms of quality. The nasty ones behave exactly as y

I have a bath in my bathroom, and I take a dump etc in the WC in the *separate* room next to it. More hygienic for a start.

I can't quite see why the word 'toilet' (although another euphemism I'll grant you) was so offensive that the often-wrong 'bathroom' seemed better. How many public 'bathrooms' in the US sense actually contain a bath?

What on earth do you mean? A toilet is literally a device meant to dispose of human waste. It is considered the "polite" word in parts of the English-speaking word, as opposed to phrases like "the shitter", but it's not a euphemism.

Completing one's toilet was originally getting dressed and washed and a toilet (or lavatory) was the place to do that, etc, but then the word got hijacked, in a long and glorious tradition of being unable to call a spade a shovelling device...

In what way? Because you care about some store that wasn't able to compete? Because you think workers are mistreated even though most of them don't actually care? Let me guess, you've got no real reason other than some silly ultra-left wing fantasy reasons that the world should be a happy place where everyone gets along and farts butterflies?

Yesterday I went to Walmart to get new light bulbs, old CFLs I had burned out. There Walmart had LED bulbs in stock, at around $20 a bulb. I ended up going to Sam's to get CFLs, an 8 pack cost less than $6.

I've tried different brands of CFL ( generic, GE, Philips, Nelson ) , many sizes as well (including a monster 65W unit) and the failure rate is high compared to the proposed life on the boxes. Initially I think it was that I had them in enclosed diffuser bulbs and I dare say with the way our Summer weather is here it killed the first batch through overheating of the electronics in the CFL bases. However, after ensuring they all had good cooling (even bare bulbs) there were still plenty of failures, so I'm just thinking that overall it would seem that CFL drivers aren't yet up to scratch, or at least the manufactures are cutting corners on the components.

I've switched to the faux-traditional-halogen replacement bulbs and they seem to be doing a lot better. Looking forward to converting to LEDs soon.

For me, CFLs have worked fine for years but I wish they would make giant LEDs you could screw in like regular light bulbs. Maybe LED technology doesn't work if you scale it up that much, I don't know for sure b/c it isn't my area of expertise. At least they have warmer color temperatures for white LEDs now.

I have Cree bulbs in my 4" recessed lights. They put out a warm color, don't make any noise, and work fine on a dimmer. I honestly can't tell the difference between them and the halogens they replaced, except they run a lot cooler. They sell them at Home Depot for about $40 each. I expect them to last at least ten years. The Cree guys know what they're doing.

If you double the efficiency, you *more* than half the cooling needed for a given amount of light.

To give an example with some math...

Suppose you need 2000 lumens from a 100 lumen/watt bulb. That means it takes 20 watts of power, and puts out 18 watts of heat.

Replace it with a 200 lumen/watt emitter that has the same light output, and it now needs only 10 watts of power, and only puts out 8 watts of heat.

All that said, I'm looking forward to this being available for bicycle lights. Doubling the efficiency means I can have double the light with the same sized battery pack, or the same amount of light with half the battery pack or some permutation thereof. Cooling isn't a big deal for bicycle lights until you get into the really high powered lights as the airflow is usually quite good.

One issue with bicycle lights, especially those popular in North America, is that their reflectors are awful. They spray light everywhere. That's only really useful when mountain biking; when cycling on the road, light sprayed into the air is wasted light, and more powerful lights create a hazard for other cyclists and motorists. A good amount of engineering goes into a proper reflector, like those used on car headlights. There are some bike lights that do it right (Phillips has some), but the ones these LE

On my bicycle I use a 30 or 40 year old chrome headlight made for use with a dynamo.

I replaced the 6v 2.4watt filament bulb in it with a high power white MES LED module designed to have 100 degree illumination. Powered by a single PP3 radio battery under the saddle, it produces a 15 foot cone of light on the road ahead of me lighting everything up to handlebar height (yes, I'm overvolting a 6v LED module but it doesnt seem to cause any problems, it still runs cool)

I've got lights like that myself. But XM-L emitters peak at about 100 lumens/watt [cree.com], not the 200 lumens/watt promised by this new technology.

Also, none of these lights really do put out the amounts of light that the emitters are rated at. For example, this says 1600 lumens, but I'll bet it's more like 800 lumens. Still, not too bad, and yes, good lights make a huge difference, and it's hard to beat the price.

These are surface mount LED modules, not bulbs. I checked one out [newark.com]. At 700 mA @12V (8.4W) gives 1040 lumens - approximately as much as a 70-watt incandescent - in a square 7mm on a side. This is only 123 lumens per watt. Max current is 1250 mA, so you could conceivably get a lot more light out of one, and presumably 1W is where the 200 Lumens/W kicks in, but that's only about a 25W incandescent equivalent - still pretty respectable considering the size. They cost about $10 in quantity 500. ROI is about 6 months vs. incandescent, or 18 months at the 200 lumens/W level.

I think I could see some interesting applications for this one. At 1040 lumens 18% of the electrical energy is converted to light, so around 6.9 W of heat. It's also too bright to look directly at.

Yes, it's a slashvertisement / press release. But LED lighting has/. common interests energy, technology, and so on. Progress is progress.

If they can just improve the efficiency a little more these might be interesting not only as a light source but as a means for spacecraft propulsion.

flashlights... and the LEDs that may be used in them, it's crazy what details they keep tabs on

They have to, since these things are typically ordered from overseas, with prohibitive return postage fees, and many times some manufacturer or vendor will try to become the cheapest by changing to LEDs of a crappy (i.e. fake) rather than Cree variety. When the item arrives, one usually has just a few days to ascertain whether it is genuine or if a refund needs to be requested from the payment service.

For comparative purposes, an incandescent bulb puts out about 52 lumens per watt. This LED is therefore about four times more efficient at converting electricity into light than the traditional lightbulb. That said, one of the big problems with LED lighting is that the light tends towards the blue end of the spectrum, whereas incandescents tend towards the red. Studies have shown that it is blue light that suppresses melatonin production, which in turn upsets the sleep/wake cycle. Similar problems have been

If only! "An upper limit for incandescent lamp luminous efficacy (LER) is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point" (wikipedia). In fact a 40W tungsten bulb outputs 12.6 lumens/watt, up to 17.5 for a 100W bulb. Incandescent bulbs aren't even in the ballpark anymore.

As to whether some people assume all light is equal, I suppose some do. But others take it very seriously [sandia.gov]. It is not an overlooked issue.

LEDs of all types (lasers excluded) have no "spike". Typical half-power bandwidth is 20 nm. It's not smooth enough for color comparisons of paint or makeup, but it's nowhere near the monochromatic implied by "spike".

Since we're talking about cree lights check out their data sheets on their own LED lighting products. The graph on pg5 looks like a spike to me.

683lm/W is the maximum luminous efficacy for light, yes, but that's green light.

To reproduce in full the solar spectrum so that it is indistinguishable from white light requires you to produce a 'white' that produces light from about 400-700nm (UV to IR borders).If you take into account flourescence and its effect on colour, perhaps 350nm is the top end.This would take perhaps 180lm/W.

As you move from near-solar (or tungsten) identical bulbs to more limited 'whites' - you get about 250-400lm/W being the maximum.This varies from pretty good white that you won't notice being different from actual white to something rather more limited, with just blue at 430nm or so, and greenish yellow at 560nm.This will to a cursory glance look right, but will have truly wretched colour reproduction.

While I *do* love to hear stories like this, and I believe that LED lighting, in some form, is the future, it dissappoints me to see that so-called "white" LEDs still produce quite poor spectra. Check out the spectrum on page 4 of the datasheet given on the MK-R series page. Compare this to the sun's spectrum. Because these are phosphor-based LEDs, you get a relatively narrow blue-violet peak (the true colour of the LED), followed by a wider hump, peaking at about yellow (the broad emission spectrum of the phosphor coating, which is down-converting those blue photons). While this looks "pure white" when you look directly at the beam, it renders colours very poorly (i.e. the reflected light from objects looks the wrong colour). This is what causes LEDs and fluorescent lights to often make a room appear sickly and food look unappetizing. Ideally, we should strive for a light which closely emulates the sun's spectrum, but this is obviously challenging.

Fortunately, there are a few next-gen LED technologies on the horizon. Quantum dot-based LEDs seem promising. By making dots of a specific size, you can precisely tune the output wavelength of a QD LED. Presumably you can combine a whole bunch of QD LEDs, each tuned to a different wavelength, to approximate the sun's spectrum. Alternatively, certain types of organic LEDs offer the ability to tune the wavelength, and similarly, produce a composite device which has a more ideal spectrum.

Still, until these materialise, plain 'ol incandescents are the only cheap light sources which produce a nice, continuous blackbody spectrum. Sigh.

In reply to a previous Slashdot article on LEDs, this minor effort: http://dr2chase.wordpress.com/2011/02/26/led-color-rendering/ [wordpress.com]The summary is, if you take decent LEDs (CREE or Luxeon) and mix the color temperatures (warm/neutral/cool) it's not bad. Your eyes adapt; the camera is much less forgiving.

It takes 8 colour swatches and measures the rendering of those. It does not do a good job of looking at actual spectrum, and there are far more than 8 colours to worry about in the real world. Look at the spectrum of an LED vs CFL some day. The CFLs are very, very spikey with lots of holes, the LEDs are continuous with more gentle peaks.

We need a new system for measuring light quality, and indeed standards agencies are looking in to it.

It's the best pocket flashlight I have ever owned. Bright and useful on "low" power (32 Lumens) and very bright on high (105 Lumens). 500 minutes of light (over 8 hours) from a single AA cell on low, or 110 minutes on high. (I'm trusting the manufacturer's numbers here, but I can verify that it actually is bright and lasts a long time.) Anyway, that's a Cree LED, and it doesn't have the horrible bluish tint of older LEDs I have bought in the past.

More recently I bought an Ecosmart light bulb at Home Depot. "Ecosmart" is a Home Depot house brand, and uses Cree LED chips. For $10 I got a light bulb that claims to give equivalent light to a 40 Watt incandescent bulb, but seems brighter than that (I think because it's much more directional; it's in a downward-facing fixture so that's fine).

And just two days ago I got a fixture that retrofits a 6" can fixture with an LED light. I bought one with the 2700K color temperature, because I like that better than the "colder" lights (bluer, which actually have higher color temperatures). I walked into the store planning to just buy a bulb for my can light fixture, and now I'm very glad I bought the whole Ecosmart fixture. I found an LED light geek web site, and the guy bought one of these just to do a teardown; he found 5 Cree LED chips inside it. Where I live, the power company is subsidizing these lights, so I only had to pay $20 for this light. This dissipates only 9.5 Watts, yet it's very bright. I love the design: it includes three spring fingers to hold it into place, but if you rotate it the fingers collapse and stop holding it. So two decades from now when the LED stops working, it will be easy to remove.

So now I want to see Cree make some sort of flush-mount ceiling fixture. I have only found a few flush-mount LED fixtures, and they are all super expensive and I can't find the 2700 K color temperature. I did find one promising looking cheap fixture, but on eBay only and it's an import from China... I have no way to be sure of the quality, other than just buying one and trying it.

My current plans are just to install some fixtures that have air gaps for circulation, so I can use the Phillips LED bulbs (omnidirectional, not directional like the Ecosmart ones). I'm going to install one of these tomorrow and see how we like it. In case the URL doesn't work right, this is a "Project Source 2-Pack White Ceiling Flush Mount" from lowes.com.

Based on my experience with these lights, we are just on the cusp of these becoming mainstream and common. I've been buying these because they are subsidized, but electronics always gets cheaper over time, and within a couple of years or so LED lights should be cheap enough without subsidy that everyone starts buying them. (Even without the subsidy, they make sense long-term versus incandescent bulbs. If you have incandescent lights, consider LED rather than compact fluorescent.)

P.S. I haven't bought these, but I wish the office where I work would buy them. These are Cree replacement lights for standard fluorescent fixtures. Some companies are making LED lights that are the exact size of a T8 fluorescent bulb, with matching pins; for $60 or $80 or so each bulb, you can replace fluorescents (but you must rewire the fixture to bypass the ballas

When i was looking into replacing a whole bunch of T12 fixtures, I liked the idea of doing LED. But just upgrading the balasts from magnetic to electronic and switching to good quality T8 tubes works out to be a way better deal. T8 bulbs already do about 90 lumens/watt for a lot less money. I also talked to a good lighting contractor who does efficiency upgrades. He said the tube retrofits don't work so well. It's better to just replace the fixtures and get LED specific fixtures. What we will hopefully get around to doing is a mixture of T12->T8 retrofits for a base lighting level, and then standard LED (PAR-20) spots to light up work areas.

When I started working with LEDs they just introduced the LM3909 oscillator - it allowed an LED (only red in those days) to blink for an entire year on a single D cell.

What keeps amazing me about LEDs is just how little energy they need to start lighting up. I'm not really into electronics anymore (was only tinkering with it since I was 11), but I recall that by using a FET for constant current [dapj.com] meant you could be pretty flexible about the supply voltage (within limits, of course, the dissipation has to go somewhere), and by researching what it was (been a while) I came across other interesting ideas [evilmadscientist.com].

As a single, simple component, I find LEDs are about the most interesting ones to experiment with (and LDRs, and NTCs, and..:) ). They are nice to introduce children to electronics because they instantly do something visible..

I've noticed a disturbing trend. Car manufacturers have been using the new lightning technologies to cram e.g. the headlights into ever smaller spaces. The resulting light beam still conforms to regulations, but because the peak intensity is much higher, those headlights are much more likely to dazzle oncoming traffic. The higher the light intensity of the lamp (lm/cm^2) the worse this will get.

There's another piece to this too. There are people in the world that will take a halogen (either projection or non-projection setup) and retrofit an HID setup in it. This causes issues:

1. The non-projection setup has no cut-off - so the light goes everywhere, which is not how good HID setups are implemented.2. The halogen projection setups - while similar to an HID setup (I have a halogen projection setup in my car) don't have some of the additional pieces to make the HID setup functional. For instance, factory setups for my vehicle have auto-levelling lamp housings to not blind oncoming traffic. Also, the cut-off (metal in the projection path to limit light output out of the top of the lamp) is in a different spot comparing non-HID projection to HID projection.

Ultimately, if you're being blinded by HID lamps - part of it could be caused by incorrect implementation. HID light, even in a correct implementation is harsher - and those sensitive to light are probably more affected; myself included.

Directed beams work reasonably well on a perfectly straight and level road. Anything else and those directed beams end up directly illuminating other drivers' eyes. Even if they're correctly set up.

I'll agree that there are lots of idiots out there with incorrectly set-up headlights. But the number of new cars with factory-standard lighting that blind me is too high for it to be an 'incorrect set-up' issue only.

It won't be long before companies figure out how to get them to work. The Phillips L-Prize bulb uses the LED as a source of photons to excite a phosphorescent material. The actual light that the bulb emits comes from the outer surface of the bulb, so directionality of the LED is irrelevant, as long as they can excite enough of the phosphor.

There is nothing to figure out. Its a problem of physics. LEDs produce heat that must be dissipated somehow. Its no good if your replacement bulb has a huge heatsink attached to it. It also brings up the problem of lights in enclosed spaces, something incandescents have no issue with.

Considering that the entire surface of an incandescent, and most of the surface of a CFL, is the area where it dissipates heat, and that both incandescents and CFLs are ALREADY too hot to touch, it's a serious improvement.

There's a measure for that, though, and it's called CRI. A perfect CRI is defined as 100, and you'd think that incandescent would have a 100 CRI but it often doesn't. Great CRI is anything >=95 and halogens often achieves that, but general purpose incandescent lamps are usually less, sometimes horrifyingly less. LED is commonly worse than 95, but almost always better than CFL. For critical viewing LED isn't always the best choice unless it's made

I have a very bright and 300+ lights christmas uhm.. "thread of lights" but I also use one of those older with small regular bulbs and those burn at a much much much yellower color so they look very miss-matching (the LED one is more "snow-white."

Also at the beginning the 3000k led spotlights I bought was rather disturbing because I wasn't very comfortable with the light color then but now I've got adjusted to it and

Growing up at 54Â N, the "daylight" colour temperature setting on monitors never made sense to me. The closest to daylight was 9300K. It never made sense until I spent a week in LA one January and saw that the sunlight really was 5800K orange when you are that far south.

its pretty common, if not standard issue now to put a patch of phosphorous over a UV led to generate the final visible light in these high powered LED's. so its very similar to what you can expect out of a CFL (course these things measure in cm)

you do get advantages though, the starting UV is generated by a crystal and not an electric arch in a vacuum so its more "rich" and if its not half assed you dont get flicker

its pretty common, if not standard issue now to put a patch of phosphorous over a UV led to generate the final visible light in these high powered LED's. so its very similar to what you can expect out of a CFL (course these things measure in cm)

And we can of course trust that the manufacturing quality is 100% on these -- that the UV light isn't leaking out. There are health problems with certain wavelengths. However, I'm sure there's nothing to worry about...

I work with LED lighting every single day, and in one instance we had an issue where a soft dome got knocked off, the spectrum is actually so near blue it looks blue, its probably safer than a blacklight you used for your posters in college

And we can of course trust that the manufacturing quality is 100% on these -- that the UV light isn't leaking out. There are health problems with certain wavelengths. However, I'm sure there's nothing to worry about...

People are so delicate, it's a wonder the human race has survived this long. I hope you don't ever go outside during the day, sunlight is full of nasty UV wavelengths.

The basic problem is there is no consensus on how to price the destruction of non-renewable resources, nor generalized damage to the environment. I would not expect a tidy solution to that issue, ever.

What's inefficient? My house needs both light and heat. 100% efficiency as far as I'm concerned.

Yes, but for *heat*, 100% efficiency from an electrical source is not the end. Any heat not supplied by lighting can be made up for with a heat pump ( > 100% efficiency) or direct heating from fossil fuel ( saves the losses in converting heat to mechanical energy and then to electrical energy). Waste heat from industrial uses can sometimes be used to. It's not hot enough for effective power generation but it is enough to heat a house.

Unless you're already using the lighting for a particular purpose. Than that "waste heat" is already going towards the heating, which is the parents point, and mine. In Canada this is the case as well. CFL's are nice and all, but regular incandescents help with general heating costs here in the winter when you're already in a room doing something.

OK. Let me know when you want to install that heat pump, and I'll start bitching about the inefficiency of light bulbs. Until then, they are just as efficient as the electric furnace I can't afford to replace.

There aren't a whole lot of people in your situation where not only is it cold enough year round to need to use the heater, but you have one of the most costly heat sources available -- electric resistance heat.

If you have any top floor ceiling fixtures or wall sconces on outside walls, much of the heat is being conducted out of your house anyway so you're not getting 100% of the waste heat into your house so you could still save some money with more efficient lighting.